Tea tree oil reduces Candido adhesion and biofilm 869 ATCC 10231 is atypical as it produces the quorum sensing 3 Dongari-Bagtzoglou A,Kashleva H,Dwivedi P,Diaz P,Vasilakos J. molecule farnesoic acid [26]but not farnesol [27].Quorum Characterization of mucosal Candida albicans biofilms.PLoS One sensing is important in biofilm formation and since farne- 2009:4:e7967.doi:10.1371/joural.pone.0007967. 4 Harriott MM,Lilly EA,Rodriguez TE,Fidel PL,Jr.,Noverr MC. soic acid has approximately 3%of the quorum sensing Candida albicans forms biofilms on the vaginal mucosa.Microbiol- activity of farnesol [27],this may have significant implica- 0gy2010:156:3635-3644. tions.It is recommended that studies investigating adhe- 5 Cotter G,Kavanagh K.Adherence mechanisms of Candida albicans. sion and/or biofilm formation use typical and well Br J Biomed Sci 2000:57:241-249. characterized strains,such as C.albicans ATCC 90028,so 6 Clatworthy AE,Pierson E,Hung DT.Targeting virulence:a new paradigm for antimicrobial therapy.Nat Chem Biol 2007:3: that results are more representative. 541-548. Diseases of the mucous membranes caused by Candida 7 International Organisation on Standardisation.ISO 4730:2004.Oil of spp.,including oral and vaginal candidiasis,are not life- Melaleuca,terpinen-4-ol type (tea tree oil).Geneva,Switzerland: threatening but may cause significant discomfort to suffer- International Organisation for Standardisation,2004. ers and episodes of disease can be recurring or chronic 8 Carson CF.Hammer KA,Riley TV.Melaleuca alternifolia (tea tree) oil:a review of antimicrobial and other medicinal properties.Clin While oral and vaginal candidiasis can be treated systemi- Microbiol Rev 2006:19:50-62. cally with oral antifungal agents,evidence from clinical 9 Hammer KA,Carson CF,Riley TV.Melaleuca alternifolia (tea tree) and animal studies indicate that there may be a role for oil inhibits germ tube formation by Candida albicans.Med Mycol topically applied TTO or individual essential oil compo- 2000:38:355-362. nents in the treatment of both infections [11,12,28.The 10 Hammer KA,Carson CF,Riley TV.Antifungal effects of Melaleuca alternifolia (tea tree)oil and its components on Candida albicans. therapeutic efficacy of terpenoid essential oils such as TTO Candida glabrata and Saccharomyces cerevisiae.J Antimicrob may be due,in part,to their ability to inhibit biofilm forma- Chemother2004:53:1081-1085. tion and reduce adhesion.However,many additional ther- 11 Vazquez JA,Zawawi AA.Efficacy of alcohol-based and alcohol-free apeutic factors such as essential oil formulation,frequency melaleuca oral solution for the treatment of fluconazole-refractory and duration of therapy need to be optimized to ensure the oropharyngeal candidiasis in patients with AlDS.HIV Clin Trials 2002:3:379-385 best possible clinical outcomes. 12 Mondello F,De Bernardis F,Girolamo A,Salvatore G.Cassone A.In In conclusion,the present study showed that TTO vitro and in vivo activity of tea tree oil against azole-susceptible and decreases biofilm formation and the adhesion of C.albi- -resistant human pathogenic yeasts.J Antimicrob Chemother 2003; cans to both biotic and abiotic surfaces.These novel data. 51:1223-1229. in addition to previously published information describing 13 Clinical and Laboratory Standards Institute.Reference Method for the effects of TTO against Candida,provide further sup- Broth Dilution Antifungal Susceptibility Testing of Yeasts,approved standard,3rd ed,document M27-A3.Wayne,PA:Clinical and Labo- port for the potential therapeutic use of TTO to treat super- ratory Standards Institute,2008. ficial Candida infections. 14 Altman S,Randers L,Rao G.Comparison of trypan blue dye exclu- sion and fluorometric assays for mammalian cell viability determina- tions.Biotechnol Prog 1993:9:671-674. Acknowledgments 15 Ramage G,Vande Walle K,Wickes BL,Lopez-Ribot JL.Stan- dardized method for in vitro antifungal susceptibility testing of The authors acknowledge the facilities,scientific and tech- Candida albicans biofilms.Antimicrob Agents Chemother 2001;45: nical assistance of the Australian Microscopy Micro- 2475-2479. analysis Research Facility at the Centre for Microscopy, 16 Jin Y,Samaranayake L,Samaranayake Y,Yip H.Biofilm formation Characterisation Analysis,The University of Western of Candida albicans is variably affected by saliva and dietary sugars. Arch Oral Biol 2004;49:789-798. Australia,a facility funded by the University,State and 17 Pizzo G.Giuliana G.Milici M.D'Angelo M.Effect of antimicrobial Commonwealth Governments.This work was supported mouthrinses on the in vitro adhesion of Candida albicans to human by Rural Industries Research and Development Corpora- buccal epithelial cells.Clin Oral Invest 2001;5:172-176. tion grants PRJ-5 and UWA-90A. 18 Colling L.Carter R.Essman M.Larsen B.Evaluation of relative yeast cell surface hydrophobicity measured by flow cytometry.Infect Dis Obstet Gynecol 2000;13:43-48. Declaration of interest:The authors report no conflicts of 19 Kwiecinski J,Eick S,Wojcik K.Effects of tea tree (Melaleuca alterni- interest.The authors alone are responsible for the content folia)oil on Staphylococcus aureus in biofilms and stationary growth phase.Int J Antimicrob Agents 2009;33:343-347. and writing of the manuscript. 20 Brady A,Loughlin R.Gilpin D,Kearney P,Tunney M.In vitro activity of tea-tree oil against clinical skin isolates of meticillin-resistant and References -sensitive Staphylococcus aureus and coagulase-negative staphylo- cocci growing planktonically and as biofilms.Med Microbiol 2006: 1 Sobel JD.Vulvovaginal candidosis.Lancet 2007;369:1961-1971. 55:1375-1380. 2 Ramage G,Mowat E,Jones B,Williams C,Lopez-Ribot J.Our cur- 21 Dalleau S.Cateau E,Berges T,Berjeaud JM,Imbert C.In vitro rent understanding of fungal biofilms.Crit Rev Microbiol 2009:35: activity of terpenes against Candida biofilms.Int J Antimicrob Agents 340-355. 2008:31:572-576. 2012 ISHAM,Medical Mycology,50,863-870© 2012 ISHAM, Medical Mycology, 50, 863–870 Tea tree oil reduces Candida adhesion and biofi lm 869 ATCC 10231 is atypical as it produces the quorum sensing molecule farnesoic acid [26] but not farnesol [27]. Quorum sensing is important in biofi lm formation and since farne￾soic acid has approximately 3% of the quorum sensing activity of farnesol [27], this may have signifi cant implica￾tions. It is recommended that studies investigating adhe￾sion and/or biofi lm formation use typical and well characterized strains, such as C. albicans ATCC 90028, so that results are more representative. Diseases of the mucous membranes caused by Candida spp., including oral and vaginal candidiasis, are not life￾threatening but may cause signifi cant discomfort to suffer￾ers and episodes of disease can be recurring or chronic. While oral and vaginal candidiasis can be treated systemi￾cally with oral antifungal agents, evidence from clinical and animal studies indicate that there may be a role for topically applied TTO or individual essential oil compo￾nents in the treatment of both infections [11,12,28]. The therapeutic effi cacy of terpenoid essential oils such as TTO may be due, in part, to their ability to inhibit biofi lm forma￾tion and reduce adhesion. However, many additional ther￾apeutic factors such as essential oil formulation, frequency and duration of therapy need to be optimized to ensure the best possible clinical outcomes. In conclusion, the present study showed that TTO decreases biofi lm formation and the adhesion of C. albi￾cans to both biotic and abiotic surfaces. These novel data, in addition to previously published information describing the effects of TTO against Candida , provide further sup￾port for the potential therapeutic use of TTO to treat super￾fi cial Candida infections. Acknowledgments The authors acknowledge the facilities, scientifi c and tech￾nical assistance of the Australian Microscopy & Micro￾analysis Research Facility at the Centre for Microscopy, Characterisation & Analysis, The University of Western Australia, a facility funded by the University, State and Commonwealth Governments. This work was supported by Rural Industries Research and Development Corpora￾tion grants PRJ-5 and UWA-90A. Declaration of interest: The authors report no confl icts of interest. The authors alone are responsible for the content and writing of the manuscript. References 1 Sobel JD. Vulvovaginal candidosis. Lancet 2007; 369 : 1961 – 1971. 2 Ramage G, Mowat E, Jones B, Williams C, Lopez-Ribot J. Our cur￾rent understanding of fungal biofi lms. Crit Rev Microbiol 2009; 35 : 340 – 355. 3 Dongari-Bagtzoglou A, Kashleva H, Dwivedi P, Diaz P, Vasilakos J. Characterization of mucosal Candida albicans biofi lms. PLoS One 2009; 4 : e7967. doi:10.1371/journal.pone.0007967. 4 Harriott MM, Lilly EA, Rodriguez TE, Fidel PL, Jr., Noverr MC. Candida albicans forms biofi lms on the vaginal mucosa. Microbiol￾ogy 2010; 156 : 3635 – 3644. 5 Cotter G, Kavanagh K. Adherence mechanisms of Candida albicans . Br J Biomed Sci 2000; 57 : 241 – 249. 6 Clatworthy AE, Pierson E, Hung DT. Targeting virulence: a new paradigm for antimicrobial therapy. Nat Chem Biol 2007; 3 : 541 – 548. 7 International Organisation on Standardisation. ISO 4730:2004, Oil of Melaleuca, terpinen-4-ol type (tea tree oil) . Geneva, Switzerland: International Organisation for Standardisation, 2004. 8 Carson CF, Hammer KA, Riley TV. Melaleuca alternifolia (tea tree) oil: a review of antimicrobial and other medicinal properties. Clin Microbiol Rev 2006; 19 : 50 – 62. 9 Hammer KA, Carson CF, Riley TV. Melaleuca alternifolia (tea tree) oil inhibits germ tube formation by Candida albicans . Med Mycol 2000; 38 : 355 – 362. 10 Hammer KA, Carson CF, Riley TV. Antifungal effects of Melaleuca alternifolia (tea tree) oil and its components on Candida albicans , Candida glabrata and Saccharomyces cerevisiae . J Antimicrob Chemother 2004; 53 : 1081 – 1085. 11 Vazquez JA, Zawawi AA. Effi cacy of alcohol-based and alcohol-free melaleuca oral solution for the treatment of fl uconazole-refractory oropharyngeal candidiasis in patients with AIDS. HIV Clin Trials 2002; 3 : 379 – 385. 12 Mondello F, De Bernardis F, Girolamo A, Salvatore G, Cassone A. In vitro and in vivo activity of tea tree oil against azole-susceptible and -resistant human pathogenic yeasts. J Antimicrob Chemother 2003; 51 : 1223 – 1229. 13 Clinical and Laboratory Standards Institute. Reference Method for Broth Dilution Antifungal Susceptibility Testing of Yeasts , approved standard, 3rd ed, document M27-A3. Wayne, PA: Clinical and Labo￾ratory Standards Institute, 2008. 14 Altman S, Randers L, Rao G. Comparison of trypan blue dye exclu￾sion and fl uorometric assays for mammalian cell viability determina￾tions. Biotechnol Prog 1993; 9 : 671 – 674. 15 Ramage G, Vande Walle K, Wickes BL, Lopez-Ribot JL. Stan￾dardized method for in vitro antifungal susceptibility testing of Candida albicans biofi lms. Antimicrob Agents Chemother 2001; 45 : 2475 – 2479. 16 Jin Y, Samaranayake L, Samaranayake Y, Yip H. Biofi lm formation of Candida albicans is variably affected by saliva and dietary sugars. Arch Oral Biol 2004; 49 : 789 – 798. 17 Pizzo G, Giuliana G, Milici M, D ’ Angelo M. Effect of antimicrobial mouthrinses on the in vitro adhesion of Candida albicans to human buccal epithelial cells. Clin Oral Invest 2001; 5 : 172 – 176. 18 Colling L, Carter R, Essman M, Larsen B. Evaluation of relative yeast cell surface hydrophobicity measured by fl ow cytometry. Infect Dis Obstet Gynecol 2000; 13 : 43 – 48. 19 Kwiecinski J, Eick S, Wojcik K. Effects of tea tree ( Melaleuca alterni￾folia ) oil on Staphylococcus aureus in biofi lms and stationary growth phase. Int J Antimicrob Agents 2009; 33 : 343 – 347. 20 Brady A, Loughlin R, Gilpin D, Kearney P, Tunney M. In vitro activity of tea-tree oil against clinical skin isolates of meticillin-resistant and -sensitive Staphylococcus aureus and coagulase-negative staphylo￾cocci growing planktonically and as biofi lms. J Med Microbiol 2006; 55 : 1375 – 1380. 21 Dalleau S, Cateau E, Berges T, Berjeaud JM, Imbert C. In vitro activity of terpenes against Candida biofi lms. Int J Antimicrob Agents 2008; 31 : 572 – 576